diff --git a/glib/gstrfuncs.c b/glib/gstrfuncs.c
index 9ee9459e7..b6ff60f51 100644
--- a/glib/gstrfuncs.c
+++ b/glib/gstrfuncs.c
@@ -380,6 +380,9 @@ g_strdup (const gchar *str)
  *
  * Returns: a pointer to the newly-allocated copy of the memory, or %NULL if @mem
  *  is %NULL.
+ * Deprecated: 2.68: Use g_memdup2() instead, as it accepts a #gsize argument
+ *     for @byte_size, avoiding the possibility of overflow in a #gsize → #guint
+ *     conversion
  */
 gpointer
 g_memdup (gconstpointer mem,
diff --git a/glib/gstrfuncs.h b/glib/gstrfuncs.h
index 47cdb0adb..2b44c9a55 100644
--- a/glib/gstrfuncs.h
+++ b/glib/gstrfuncs.h
@@ -253,9 +253,9 @@ GLIB_AVAILABLE_IN_ALL
 gchar*                g_strescape      (const gchar *source,
 					const gchar *exceptions) G_GNUC_MALLOC;
 
-GLIB_AVAILABLE_IN_ALL
-gpointer              g_memdup	       (gconstpointer mem,
-					guint	       byte_size) G_GNUC_ALLOC_SIZE(2);
+GLIB_DEPRECATED_IN_2_68_FOR (g_memdup2)
+gpointer              g_memdup         (gconstpointer mem,
+                                        guint         byte_size) G_GNUC_ALLOC_SIZE(2);
 
 GLIB_AVAILABLE_IN_2_68
 gpointer              g_memdup2        (gconstpointer mem,
diff --git a/glib/tests/strfuncs.c b/glib/tests/strfuncs.c
index d6eaee385..ab93f8602 100644
--- a/glib/tests/strfuncs.c
+++ b/glib/tests/strfuncs.c
@@ -205,6 +205,8 @@ test_is_to_digit (void)
 static void
 test_memdup (void)
 {
+  G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+
   gchar *str_dup = NULL;
   const gchar *str = "The quick brown fox jumps over the lazy dog";
 
@@ -219,6 +221,8 @@ test_memdup (void)
   g_assert_cmpstr (str, ==, str_dup);
 
   g_free (str_dup);
+
+  G_GNUC_END_IGNORE_DEPRECATIONS
 }
 
 /* Testing g_memdup2() function with various positive and negative cases */